Probably the most important thing to ask before you do anything is, do you have someone who can fix the computer if you screw it up? Installing Linux means removing Windows, so if you get half way through and get stuck, you’re going to be left with a computer that doesn’t work. Will you be able to recover it, or have someone who can?
Once you’re on the desktop, most of what you do is going to be very similar to Windows, except most of the programs will have different names. I would imagine that the vast majority of people can use Linux once it’s installed, especially if they’re in your situation, where they’re not used to computers and don’t have any habits from Windows.